This relates generally to imaging systems and, more particularly, to imaging systems with phase detection capabilities.
Modern electronic devices such as cellular telephones, cameras, and computers often use digital image sensors. Imager sensors (sometimes referred to as imagers) may be formed from a two-dimensional array of image sensing pixels. Each pixel receives incident photons (light) and converts the photons into electrical signals. Image sensors are sometimes designed to provide images to electronic devices using a Joint Photographic Experts Group (JPEG) format.
Some applications such as automatic focusing and three-dimensional (3D) imaging may require electronic devices to provide stereo and/or depth sensing capabilities. For example, to bring an object of interest into focus for an image capture, an electronic device may need to identify the distances between the electronic device and object of interest. To identify distances, conventional electronic devices use complex arrangements. Some arrangements require the use of multiple image sensors and camera lenses that capture images from various viewpoints. Other arrangements require the addition of lenticular arrays that focus incident light on sub-regions of a two-dimensional pixel array. Due to the addition of components such as additional image sensors or complex lens arrays, these arrangements lead to reduced spatial resolution, increased cost, and increased complexity.
Yet another arrangement for electronic devices to identify distances includes using phase detection pixels. However, conventional phase detection pixels may have limited dynamic range and undesirably slow readout times.
It would therefore be desirable to be able to provide improved phase detection pixel arrangements for image sensors.